10 valvular heart disease (pathology)

Question 1

What are the major causes of valvular disease?

Answer 1

• congenital (most common= bicuspid aortic valve)
• acquired
  
  • aortic stenosis (senile calcification)
  • aortic insufficiency (dilation of ascending aorta related to HTN and aging)
  • mitral stenosis (rheumatic heart disease)
  • mitral insufficiency (myxomatous degeneration)
  • stenosis more frequent than insufficiencies

Question 2

Describe dystrophic calcification

Answer 2

• damage caused by wear and tear complicated by deposits of calcium phosphate
• distinct from atherosclerosis but shares risk factors (hyperlipidemia, HTN, inflammation)
• e.g. calcific aortic stenosis, mitral annular calcification

Question 3

What is the most common valvular abnormality?

Answer 3

Calcific aortic stenosis

Question 4

Describe calcific aortic stenosis

Answer 4

• most common in “senile” valves; 8th/9th decade
  
  • presents earlier (5th/6th decade) in bicuspid and unicuspid valves; esp with the notch mutation
• clinical effects:
  
  • increased pressure= LV hypertrophy
  • angina, ischemia, CHF (50% with CHF die within 2 years)
  • syncope
• treatment= valve replacement

Question 5

Grossly, describe calcific aortic stenosis

Answer 5

• heaped up calcified masses in cusps primarily at the bases
• free cuspal edges not involved
• no fusion of commisures

Question 6

Describe mitral annular calcification

Answer 6

• degenerative calcific deposits on fibrous ring, at the base of the valve that usually does not affect valve function
  
  • calcifications= sites for thrombi/infection
• women >60 yo
• increased in patients with myxomatous (degenerative) valves or elevated LV pressure

Question 7

Describe myxomatous degeneration of the mitral valve

Answer 7

• aka mitral valve prolapse
• one or both leaflets enlarged, hooded, redundant, floppy (myxoid)
  
  • prolapses/balloons back into left atrium during systole
• very common (3% of adults), esp in young women
  
  • feature of marfan syndrome
• usually no serious complications
• hear a midsystolic click on auscultation

Question 8

What is the most important complication of rheumatic fever?

Answer 8

Progression to chronic valvular dysfunction (mitral stenosis)

Question 9

Describe the pathophysiology of rheumatic fever

Answer 9

• occurs following an episode of group A strep (pyogenes) pharyngitis
• immunologically mediated (Ab against M protein cross react with glycoprotein antigens in heart, joints, and other tisues
• acute, multisystem, inflammatory disease with major cardiac manifestations

Question 10

Describe the morphology of rheumatic fever

Answer 10

• widely disseminated inflammatory lesions found in many sites
• pancarditis (affects all layers)
  
  • bread and butter pericarditis
  • myocarditis (Aschoff bodies)
  • endocardium/ left sided valves with fibrinoid necrosis and verrucae
  • subendocardial (MacCallum) plaques

Question 11

What is an Aschoff body?

Answer 11

• the classic lesion of acute rheumatic fever
• foci of swollen eosinophilic collagen surrounded by T lymphocytes, plasma cells and plump macrophages
• anitschkow cells, caterpillar cells

Question 12

What are the major complications of chronic rheumatic heart disease?

Answer 12

Organization of inflammation and fibrosis leads to…

• thickened valve leaflets
• fusion of commissures (fishmouth/buttonhole deformities)
• fusion/thickening of chordae tendinae

**Major effect is mitral stenosis
(also aortic>tricuspid>>pulmonary involvement)

Question 13

What are the consequences of mitral stenosis?

Answer 13

• leads to L atrial dilation (sometimes thrombus formation)
• reduces cardiac output (mechanical obstruction prevents filling of LV)
• result= pulmonary congestion, eventual right ventricular hypertrophy and right sided heart failure

Question 14

Describe the JONES criteria

Answer 14

The major manifestations of rheumatic fever:

• joints (migratory polyarthritis)
• heart (pericardial rub, weak heart sounds, tachycardia, arrhythmia)
• nodules (subcutaneous on extensor surfaces)
• erythema marginatum
• sydenham chorea

Question 15

What are some minor manifestations of rheumatic fever?

Answer 15

• fever
• arthralgia
• elevated acute phase reactants

Question 16

Describe acute rheumatic fever

Answer 16

• 1-4 weeks after group A (beta hemolytic) strep pharyngitis
• children 5-15
• ASO (Anti-streptolysin O) titers and Abs to DNAse B

Question 17

What are the 2 basic clinical forms of infective endocarditis?

Answer 17

• acute
  
  • highly virulent organism, normal valve
  • necrotizing ulcerative invasion infections (erosion of myocardium -> ring abscess), requiring surgery
  • 50% mortality
• subacute
  
  • low virulence, deformed valve
  • less destructive lesions (fibrosis and granulation tissue reaction at the base of vegetation)
  • respond to antibiotics

Question 18

What are the top 3 causes of IE?

Answer 18

1. strep viridans (50-60% of infected deformed valves)
2. staph aureus (10-20% of IE overall)
   **most common organism in IVDU
3. other commensal organisms of the mouth (esp staph epidermidis in prosthetic valves)

Question 19

What valves are most commonly affected by IE? In IVDU?

Answer 19

Overall; mitral and aortic most common

IVDU= tricuspid valve

Question 20

Describe the Duke criteria

Answer 20

**To measure likelihood of IE:

• major
  
  • positive blood cultures
  • echo findings (valve mass/abscess)
  • new valve regurgitation (new murmur)
• minor
  
  • predisposing heart lesion or IVDU
  • fever
  • uncommon symptoms from emboli (petechia, janeway, osler’s, roth spots)

Question 21

What are the common complications of IE?

Answer 21

• valvular insufficiency or stenosis
• possible heart failure
• myocardial abscesses -> possible perforation
• vegetations break off -> embolic complications
• glomerulonephritis (immune complexes)

Question 22

Describe nonbacterial thrombotic endocarditis

Answer 22

• depositions of small masses of fibrin, platelets, and other blood products on leaflets (along the lines of closure)
  
  • not destructive or inflammatory
• often in debilitated patients (cancer, sepsis), and may result in emboli and infarcts

Question 23

What causes nonbacterial thrombotic endocarditis?

Answer 23

• hypercoagulable states (cancer, sepsis)
• mucin producing adenocardinomas of the GU/GI tract
• endocardial trauma (e.g. from catheter)

Question 24

Describe Libman-Sacks endocarditis

Answer 24

• most characteristic cardiac manifestation of the autoimmune disease systemic lupus erythematosus
  
  • mitral/tricuspid involvement
  • antiphospholipid antibodies present
• either or both sides of leaflets (may also be on endocardium)
• may have intense inflammation

Question 25

Describe the locations of the 4 types of vegetative endocarditis we discussed

Answer 25

* Rheumatic Heart Disease * mitral usually (sometime +aortic) * inflammation and fibrosis * Infectious Endocarditis * mitral and aortic most common * Non-Bacterial Thrombotic Endocarditis * any valve (small along closure) * sterile, nondestructive, noninflammatory * Libman-Sacks Endocarditis * mitral and tricuspid * both sides of leaflets

Question 26

Describe carcinoid syndrome

Answer 26

* flushing, cramps, nausea, vomiting, diarrhea * from carcinoid tumor producing serotonin, kallikrein, bradykinin, histamine, prostaglandins, and tachykinins * serotonin and bradykinin in activated by... * MAO in pulmonary vasculature * passage through liver * 50% of pts with carcinoid syndrome have plaque-like **fibrosis of _right_-heart endocardium and valves** * tricuspid insufficiency * pulmonic stenosis

Question 27

What are the complications of artificial valves?

Answer 27

* both increase risk of IE! * mechanical * thromboembolic complications * need to take anticoagulant * bioprosthesis * structural deterioration (50% need replacement by 15 years)